Upgrade to GitHub-native Dependabot (#281)

.github/dependabot.yml

@@ -0,0 +1,15 @@
+version: 2
+updates:
+- package-ecosystem: npm
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+  reviewers:
+  - lowlighter
+  assignees:
+  - lowlighter
+  ignore:
+  - dependency-name: vue-prism-component
+    versions:
+    - 2.0.0